No-capacity control for condensers



April 28, 1925. 1,536,039

J. T. BRADLEY NO CAPACITY CONTROL FOR CONDENSERS Original Filed April' 5', 1923 Patented Apr. 28, .1925

JOHN n'naannay, or TUTUILA, sauce.

ITO-CAPACITY CONTROL FOR CONDENSERS.

Application. filed April 3, 1928, Serial No. 629,737. Renewed February 25, 1925.

To all whom it may concern:

Be it known that I, JOHN T. BRADLEY, a citizen of the United States, residing at Tutuila, Samoa, have invented certain new and useful Improvements'in No-Capacity Controls for Condensers, of ,yvhich the following is a specification.

The invention relates to controlling means for variable condensers, such as are in common use in radio of the Vernier type, wherein a large number of plates are adjusted for a coarse adjustment and a small number for a Vernier adjustment. With apparatus of this nature a great difiiculty has been found to be that the placin of the hand of the operator upon the knob 0% the dial for adjustment, of the condenser introduces the capacity of the body into the circuit so that when the combined capacity of the condenser and body has been brought to the proper point the removal of the hand throws the tuning out.

An object of the resent invention is the provision of means which the condenser may be adjusted bot as to coarse adjustment and as to fine adjustment without a touching the knob of the dial and therefore without introduction of the objectionable capacity effect. A further object of the invention is the provision of means whereby a condenser may be adjusted by both movements with one hand and without change of the position of the hand, and therefore such that one condenser can be adjusted with each hand simultaneously. A further object of the invention isthe provision of a Vernier control susceptible of exceedingly fine adjustments.

screw 13. By utilizing p Illustrative embodiments of the invention are shown in the accompanying drawing, wherein Fig. 1 is a plan view; L

Fig. 2 is a view similar to Fig. 1 with the top of the knob removed,

Fig. 3 is a detail section to an enlarged scale upon broken line 3, 3 ofFig. 1.

The vernier condensers of the type to which the present invention is applicable have their coarse adjustment controlled by a tube or sleeve, as 10, and their fine adjustment by a shaft 11 passing. through the sleeve 10. Oustomarily, the dial 12 is secured to the sleeve 10 as by means of a set arts as shown in the drawing applicant is able to replace 1, existing dialswith the improved, dial of the invention. To apply the invention to dials for such replacement" the knob 14 is made in two parts as shown, the part 15 being integral with the disk of the dial l2, and the set screw 13 being provided therein. To adjust the vernier parts bymeans of the shaft 11 the usual knob, which is applied to such shaft outside of the dial, as 12, is replaced b means of a worm wheel 16, which is provi ed with internal screw threads, and which may therefore be screwed upon the end of the shaft 11 in lace of the usual knob referred to. In t e event that the shaft 11 is found not to be threaded, the set screw 17 provided upon the up-standing flange 18 of the worm wheel 16 may be utilized to secure the wheel upon the shaft. If the shaft is screw threaded the set screw 17 acts as an additional securing means to prevent rotation of the wheel upon the screw thread.

To receive the worm wheel 16 a recess 19 is provided within the portion 15 of the knob 14. To cover the wheel a cap 20 having a recess 21 complemental to the recess 19 is provided, which cap has an additional smaller recess 22 for reception of the end of the shaft 11 and the flange 18. The cap 20 may be secured in place upon the portion 15 by means of screws 23.

To operate the worm wheel 16, a worm 24 is shown carried by a shaft 25 having a knob 26 at its extremity for. grasp by the hand of the operator. An offset recess 27 is provided in each of the recesses 19 and 21 to accommodate the worm 27. To revent longitudinal movement of the sha 25 due to its action against the worm wheel, annular flanges or rings 28, 29 are provided rigid with the shaft 25, which rings engage semicylindrical grooves in the portions 15 and 20 of the knob 14. The grooves engaged by the rings 28, 29 are spaced from the recess, leaving a wall of material to receive the push of the rings.

With the parts assembled as illustrated,

the knob 26 ma be grasped by the hand of the user and'tlie dial may be turned for coarse adjustment of the condenser by swinging the arm in the are of a circle, as indicated by the arrow on Fi 1. When the desired coarse ad'ustment as been secured a revolution 0 the sliaft 25 may be caused by twirling the knob 26 by the fin- .gers, WhlCh twirling may, if desired, cause a movement of 360 of the worm wheel 16 movement may control the vernier portion of the condenser.

2. A vernier condenser control comprising, in combination, a dial, means to move said dial for coarse adjustment of a condenser, means whereby said first named means by a different form of movement may control the vernier portion of the condenser.

3. A vernier condenser control comprising, in combination, a dial, a coarse ad ustment condenser sleeve; a vernier shaft,

means to secure said dial to the coarse adjustment sleeve, a shaft co-a'cting with said dial by bodily movement to cause revolution of the dial, means whereby said shaft by rotation about its axis may cause revolution of the vernier shaft of the condenser.

4. A vernier condenser control comprising, a dial, a knob upon said dial, means to secure said dial to the coarse adjustment sleeve of a condenser, a wheel adjacent said dial, meansto secure said wheel to the vernier shaft of the condenser, means projects ing from said wheel to cause revolution of said vernier shaft, said last named means coacting with the dial to cause revolution thereof .by bodily motion about the axis of the shaft as a center for coarse adjustment of thecondenser.

5. A vernier condenser control comprising, in combination, a dial, meansto secure said dial to the coarse adjustment sleeve of the condenser, a worm wheel, means to secure the worm wheel to the vernier shaft of the condenser, ashaft having a worm to coact with said wheel, means to secure said shaft to said dial whereby movement of the worm shaft about the axis of the sleeve maycauserevolution of the dial and sleeve, and whereby revolution of the worm shaft upon its axis may cause revolution of the vernier shaft.

6. A vernier condenser control comprising, in combination, a dial having a recess,

. means to secure said dial to the coarse adjustment sleeve of a condenser, a worm wheel seatedin said recess, means to secure the-worm wheel to the vernier shaft of the condenser, a worm shaft having its-worm seated in an oifset ofvsaid recess and in mesh with said worm wheel, flanges on said worm shaft seated in separaterecesses in said dial to prevent longitudinal movement of the I worm shaft, a cover -for said recess, said cover having recesses complementary to the recesses of said dial.

1 JOHN '1. BRADLEY. 

